Image forming apparatus

Abstract

In an image forming apparatus ( 1 ) utilizing electrophotographic technology, position and posture of a laser scan unit ( 5 ) with respect top a frame ( 13 ) is adjusted easily without cost rise and upsizing of the apparatus. Semicircular recesses ( 53 ) and an elongate hole ( 54 ) are formed at each of three fixing portions ( 52 a , 52 b and 52 c) in the vicinities of side faces ( 51 b) and a rear face ( 51 c) of a housing ( 51 ) of the laser scan unit ( 5 ), and an adjuster 30 serving as a spacer is attached to each of the fixing portions ( 52 a , 52 b and 52 c). Each adjuster ( 30 ) is elected among a plurality of kinds of adjustors respectively having different thicknesses manufactured by press working of metal plates commercially produced and having different thicknesses with using the same dies. The adjustor has a pair of semicircular engaging portions 30 b and a coupling portion 30 a perpendicular to and coupling the engaging portions ( 30 b).

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an image forming apparatus comprising, a laser scan unit that forms a latent image on a surface of a photoconductor drum by irradiating laser beams while scanning.[0003]2. Description of the Related Art[0004]In a conventional image forming apparatus such as a laser beam printer that utilizes electrophotographic technology, an optical system for scanning laser beams is unitized as a laser scan unit in consideration of workability of assembly or easiness of maintenance. Such a laser scan unit is previously adjusted to have a predetermined quality when components thereof are assembled as a unit. Thus, it is no need to adjust the laser scan unit after the assembly, so that it can be handled as a component, that is, a black box.[0005]As for the attachment of the laser scan unit on the image forming apparatus, the laser scan unit is generally fixed on a metal frame provided inside the image fo...

AI Technical Summary

Benefits of technology

[0009]A purpose of the present invention is to provide an image forming apparatus that enables to control position and posture of a laser scan unit which is unitized as a black box easily and quickly when the laser scan unit is fixed on a frame, while preventing the cost rise and upsizing of the apparatus.

[0011]According to such a configuration, the position and posture, especially, the inclination of the laser scan unit with respect to the frame in a vertical plane or vertical planes including the main scanning direction and / or sub-scanning direction can be adjusted by a simple method to select the thickness of the adjuster attached to each of the three fixing portions of the housing of the laser scan unit. Consequently, the position and posture of the laser scan unit with respect to the frame is precisely adjusted easily, so that quality of an image formed on a recording paper sheet can be increased.

[0012]Furthermore, the metal plates commercially produced have various thicknesses so that the thickness becomes thicker, for example, by 0.1 mm, and the thickness accuracies of them are high at all. Therefore, various kinds of the adjusters can be made with using the same dies by changing the thicknesses of the metal plates as a material of the adjusters, so that the cost for forming the dies can be reduced. Consequently, the cost for forming each adjuster becomes inexpensive.

Problems solved by technology

The wedge shaped member, however, becomes larger than the laser scan unit, so that it causes upsizing of the image forming apparatus.

Furthermore, the wedge shaped member is necessary to be finished to a predetermined quality, so that it causes the cost rise.

It, however, needs a space to provide the spacer slidably, so that it is difficult to downsize the image forming apparatus.

Furthermore, the insertion of the spacer between the laser scan unit and the frame causes the deformation of a housing of the laser scan unit.

Such a configuration, however, needs angle adjustment of the light source after attachment of the optical system for scanning laser beam on the image forming apparatus, so that it is impossible to unitize the optical system for scanning laser beam as a laser scan unit that needs no adjustment.

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